There was a thread back some time ago about installing A/C in a shop and I advised that using pleated filters would be advisable and far better then what they come with. In this post by Jay Bates he shows his approach to the issue where he has a few thru the wall units (like hotels) and his method to properly filter the air thus protecting the unit and keeping it from needing servicing every month. See https://jayscustomcreations.com/2019/10/mini-split-filters/ This apporach can/should be used for window units as well. Keeping the evaporator coil (indoor coil) free of sawdust and dirt will allow the unit to work properly, last way longer (years) and save money by working more efficiently and longer. Just make sure to do block the discharge air into the room. If you find the unit freezing up it's likely either restricted air (dirty indoor coil) or a fan issue.